Water tube steam generator



Sept. 26, 1933. G, L., coLBlE WATER TUBE STEAM GENERATOR Filed Sept. 15, 1931 4 Sheets-Sheet 1 INVENTOR G05 C'O//.

BY mwa/L@ ATTORNEY Sept. 26, 1933. G. L. coLBlE 1,928,445

v WATER TUBE STEAM GENERATOR E Filed Sept. 15, 1931 4 Sheets-Sheet 2 76T 1 JI 1* .A I 75 l i 1 i S i!) Q0 l ORN Sept- 25, 1933' G. L. coLBlE WATER TUBE STEAM GENERATOR Filed Sept. 15, 1931 4 Sheets-Sheet 3 ATTRNEY Sept. 26, 1933. G. l..` coLBlE 1,928,446

WATER TUBE STEAM GENERATOR Filed Sept. 15, 1931 4 Sheets-Sheet 4 7l 14'. 4 5 w Fl 5- 5- l 751/7/ 6/ 75 7,/ Imm mmm/67 mlm INVENTOR ATTORNEY Patented Sept. 26, 1933 UNITED STATES PATENT OFFICE WATER TUBE STEAM GENERATOR Application September 15, l1931 Serial No. 562,931

14 Claims.

My invention relates to a novel form of electrically heated steam generator and more particularly to an internally vheated water tube, the heating member being centrally disposed within the water tube.

More particularly the invention is designed to produce a multiple unit construction of a standardized steam generator in which any desired number of units may be connected together toV form .a steam generator of any desired capacity and of the proper external contour to lit into any particular space. 'Ihis last feature is particularly important in the heating of trains which are drawn out of .and into terminal stations by electrical locomotives, but which are heated by steam driven locomotives during the rest of each run. There are now in use, oil red steam generators on electric locomotives, but due to the limited space for this purpose, it has been dinicult torarrange them in a practical way. With my multiple unit arrangement, the units may be distributed about the cab in differently arranged assemblies and all connected together to operate as one unitary system. It is also adapted for use in commercial boiler rooms, where the modern tendency is to arrange such boiler rooms to provide clean, comfortable surroundings for the attendant, eliminating the coal stokers, and requiring only the attention of an engineer who will control the entire operation from a switch board.

This type of steam generator might be termed a cellular unit structure in which each cell com- Y prises a water tube having an electrical heating element within it capable of producing a predetermined quantity of heat and a predetermined volume of steam. Thus, each cell or unit is an independent steam generator which can function as such, by reason of the particular assembly or the vertical relation of each of said units.

The vertical relation of each cell in the cellular structure is quite important to permit the operation of. any desired one or group of cells, which would not be possible in tubes arranged otherwise, since each tube in a vertical position always has one denite quantity of Water withiny it which is changed to steam, each tube generating the same amount of steam, thus permitting the elimination of any number of tubes from opera- Vtion without aiecting the others.

With this assembly, it is also possible to contro the generation of steam by means of electrical switches, thermostats orv the like, in such manner as to generateany desiredquantity, from the full capacityof allthe runits down to the capacity of (Cl. 21S-38) one single unit thus providing any desired quantity of steam when it is required.

A steam generator of this character is highly desirable for use where requirements for steam vary over certain periods each day, for instance, 69 if used in a commercial plant', the requirement may be for full capacity in the morning, half the capacity in the afternoon and perhaps a small fractional part of the capacity to provide heat for the building at night, or there may be occasions such as the noon hour period when the entire steam plant operation could be suspended. The latter is an example of extreme operating conditions which can be effectively approached with the type of steam generator herein dis- 79 closed. y

When used in a locomotive all of the cells would be used for a full train of ten cars for instance and a proportionate number of cells for any number of cars less than ten.

Steam may be generated in a single cell, groups of cells or from the entire cellular assembly'. Each cell or group of cells may operate independently, yet they are so correlated that all of the cells can operate in unison, each cell cooperating one with another. l

Thus it may be stated that with my arrangement I provide an eliicient and practical type of electrically heated steam generator having three points of distinction which differ from commercial boilers of any type, namely, flexibility of form, flexibility of control and flexibility of function.

Other known types of electrically heated steam generators may function in part under conditions similar to those mentioned above but could not operate as effectively and eiciently as the structure of my invention. So far as is known, no attempts have been made to develop a cellular unit structure having an electrical heating element within veach cell, with an assembly such as shown and disclosed in the drawings and specifications.

Other features ofconstruction include interchangeable standardized electrical heating elements and Water tight envelopes surrounding same which are supported at their upper ends in the steam headers, leaving the lower ends free to expand longitudinally, but guided laterally.

By my inventionI provide a novel arrangement of an electrically heated water tube boiler which comprises a plurality of one or more water tubes, each one of which is a separate steam generator. Water supply and steam headers are provided at the tube ends, each header having branch water inlet and steam outlet connections which are joined with manifolds surrounding the headers.

The heat is supplied by means of a novel form of electrical resistance unit which is arranged Within an envelope, said envelope being inserted within the water tube, their relative diameters being such as to leave a narrow annular water passage between the shell and the tube. Said envelope is supported at its upperv end leaving the lower portion free to expand longitudinally when heated. Resistance' wire, of a very heavy cross section, is supported by spaced discs of refractory material, said discs being mounted between ribs or shoulders formed on a casing surrounding same.

Any conventional type of feed water regulator and pump may be used as a means for maintaining a constant water level within the generator tubes.

The best form of apparatus at present known to me embodying my invention is illustrated in the accompanying four sheets of drawings in which Fig. 1 is an end elevation of one form of my invention with parts broken away.

Fig. 2 is a side elevation of the structure shown in Fig. 1.

Fig. 3 is a plan View of the structure shown in Fig. 1, also showing a wiring diagram.

Fig. 4 is an enlarged vertical section taken on the lines 4--4 of Fig. 3.

Fig. 5 is a vertical section taken on the lines Fig. 6 is a cross section taken on the lines 6 6 of Fig. 4, and

Fig. 7 is a cross section taken on the lines 7-7 of Fig. 4.

Throughout the drawings like reference characters indicate like parts. In the preferred embodiment here shown the generator 10 comprises a plurality of tubular members or water jackets 12 preferably arranged vertically and joined at their upper ends 14 to a series of steam headers 16, and at their lower ends 18 to a corresponding series of water headers 20. To retain the tubes 12 within the headers, I roll the ends and force same into annular recesses 13 in the header openings 15 to form water and steam-tight joints, see Figs. 4 and 5. The rolling operation is vperformed by means of a tool which is adapted to be inserted through the upper and lower header openings, the upper openings being closed by the heating unit mounting member to be described hereafter and the lower openings being closed by caps 17 which are inserted through the water inlet opening 19, in the header 20, as best shown in Figs. 4 and 5. i

Within each water jacket 12 is suspended a centrally disposed standardized heating unit generally indicated as 22, which comprises an electrical heating member generally indicated as 23, contained within a water-tight and steamtight envelope 24.

The said envelope 24 is closed at its lower end and has an outwardly flared flange 26 at its upper end, which fits over an annular internal shoulder c 128, in an opening 25, inthe upper wall of the within the water jacket and leaverthe lower end of the envelope 24 free for expansion and contraction relative to tube 12, in both radial and axial direction, if same occurs.

The electrical heating element 23 comprises a continuous strand of resistance wire 34 of large cross section which is passed through spacer discs 36 of insulating material, to provide several vertically disposed lengths in a xed, spaced relation, one with another.

rlwo halves of a sleeve or casing 38, having internal circumferential ribs 40 or the like, are placed around the discs 36, said discs being confined between the ribs 4G. After assembling, the sleeve 33 may be welded at various points along the joints as indicated at 42, (see Figs. 4, 5, 6 and 7) and two rings 44-44 are placed around the sleeve at the top and welded thereto, leaving a space between, to accommodate a split insulating collar 46. Since the two halves of the casing 38 are slightly separated, as indicated in Figs. 6 and 7, open spaces will be left between, through which. radiated heat can flow from the resistor 34 to the inner surface of the envelope 24; thence by conduction the heat will pass to the water or steam on the other side of such wall. Other openings may be provided in the casing 38 if desired.

Vv'ithin the lower end of the envelope 24 is a centering block 48 of insulating material, having a recessed portion 50 adapted to receive the lower` end of the casing 38, and to maintain same in a xed spaced relation to the envelope 24. A space is left between the bottom of the casing 38 and the recess 50 to allow for longitudinal expansion of the said casing relative to envelope 24.

To assemble an entire heating unit an envelope 24 is inserted into a tube or jacket 12 through one of the openings 25 in the upper wall of the steam header 16. The flange 26 around the open, upper end of such envelope 24 is seated against suitable packing 27, resting on shoulder 28. A screw threaded collar 52, having an internal recess 54, is screwed into an internally threaded upper portion 56 of each opening 25, the lower surface of said collar being brought into clamping engagement with the flange 26, on the shell or envelope 24. A portion of said screw threaded collar 52 projects above the top of the steam header 16.

After the electrical resistance unit is assembled. within the casing 38 as previously described, two halves of the split insulating collar 46 are placed around the upper portion of the sleeve between the rings 44-44 and the whole is then inserted in the shell 24. The lower end of the caf:- ing 38 is placed in the recess 50, within the insulating block 48, and the split collar 46 is fitted into the recess 54, in the threaded collar 52. The top of the said collar 46 projects slightly above the top of the threaded collar 52. To retain this assembly within the envelope 24 an internally threaded annular cap 60 is screwed onto the projecting portion of the threaded collar, said. cap be ing provided with an inwardly extending flange 62, which is adapted to be brought into contact with the upper surface of the projecting portion of the split insulating collar 46.

The annular threaded collar 52 and its contained insulating ller elements, the split ring 54 and upper disk 36, together form a removable closure for the open end of the envelope 24. and serve as means of supporting that end of the electrical heating assembly including resistor spacing disks 36 and casing 33.

Terminals 61 are provided for thev ends of the resistance wire 34 which comprise internally threaded lugs 63, adapted to be screwed or welded on the threaded ends -of the resistance lill output according to the requirements.

.wire 34, said lugs having threaded Shanks which project up through an insulating cap 67 resting on' the upper ring 44. Straps or any other form of connection 71, may be used to connect the units together, the straps being placed over the ends of shanks 65 and secured thereon by nuts 73.

It will be observed from the foregoing descriptionL of the standardized. heating unit that an interchangeable unit has been developed which can be inserted in anyl boiler constructed according to this invention, or can be transferred from one to another portion of any such boiler. It will also be observed that the electrical heating assembly of resistor, resistor. supports and the closure carrying these elements, forms a standardized unit which can be used with any envelope 24.

Each steam header, connected water header and set of tubes with heatingunits therein contained, constitute a complete boiler section which can be used by itself when equipped with the properfeed water and steam pipe connection; or any desired number of such boiler sections can be hooked up together to give the required steam producing capacity, as indicated in' Fig. 3.

With the form of structure disclosed, it is also possible to control the generation of steam, by means of electrical switches 90 as shown in the wiring diagram connected to the terminals 61 of one row `of heating elements. Said switches 90are so arranged that one or a group of heating elements maybe cut in or out oi the electrical circuit thereby controlling the volume of steam Automatic control through a thermostat 92 be had if desired. The thermostat at 92, or the switch (shown in shunt therewith, cuts out an entire header section of cells all at once. The

'l switches 90 are only shown in connection with one row oi.'l steam generator tube heating elements, but it is to be understood that all of the elements are to be similarly'connected. It is therefore possible to operate the necessary number of cell units at full power and maximum fthat my invention discloses a construction of great exibility for adaptation to different requirernents as to output, and installation space available, with a uniform low cost of manufacture (resulting-from mass production of stand- "ardized unitsluniform high efficiency and low cost of replacement and repairs.-

In addition to the foregoing form of structure I provide a novel form of water supply piping and steam outlet piping, which are shown in lFigs. 1, 2 and 3.

Regarding the water inlet, I provide a substantially U-shaped supply tube 64, each branch or arm of which has a number oI^ downwardly disposed branch tubes 66 projecting therefrom,

the ends of which may be formed integrally with 'lstantially U-shaped tube '7.4 having downwardly disposed branch tubes '76, spaced along eithery branch of the U and preferably having their ends formed integrally with a steam header plate '78. Said header plates are secured to the ends of the steam headers 16, (as shown in Fig. 3) in positions which place the outlet openings 79 of the branch tubes '76, in alignment with the centers of the transverse rows of tubular water jackets l2. a main steam discharge pipe 80, is joined at 82 to the iianged end of the branch 84 at the middle of the bend the U-shaped tube 74 and a safety valve 86 is mounted on said tube '74 adjacent the branch 81.1..

By this novel means of water connection an even distribution of water is supplied to the jackets and proper circulation within said jackets is assured, also, the generated steam is permitted to pass oil rapidly through each of the individual branch outlets leading into the main steam outlet.

At the bottom oi the water header 20, l provide a supporting base, which as here shown, cornprises two angle iron members 88, secured to the bottoni headers 20 of the water headers 20 as shown in Figs. 1 and 2.

To maintain a constant water level within the Water jackets 12, a boiler feed water pump 90 is provided in combination with a conventional form of feed water regulator indicated at 92, and a pressure controlled, automatic regulator valve 94. See Fig. 2. As this attachment forms no part of my invention and is in common use I will not describe its construction and operation further than to say that variations in water level in cylinder 92 produce the proper opening or closing movement of steam throttle valve 96, which will in turn stop, start, accelerate or slow down the operation of feed water pump 96, so asto prevent large fluctuations of Water level in the boiler beyond predetermined limits.

It is to be understood that the usual insulating material will be supplied to cover the structure after it is assembled and that variousk changes can be made in the details of costruction here shown and described, as forming one embodiment of my invention, any such modications still being within the scope of the nvention here claimed ii the principles of operation and results above explained substantially preserved.

Having described my invention, I claimz.

l. In an electrically heated steam gen an outer cellular structure comprising of vertically disposed tubes open both ends and arranged side by side, each such tube ccnstituting the envelope of a separate steam` generating cell, electrical heating means within. each cell of said structure, header members join-- ing said cells in multiples, a system of Water inlet and steam outlet piping adapted to be connected to all of said headers and means for controlling the generation of steam within each cell; whereby a multiple unit steam generator results, in which as many cells as necessary can be operated at maximum eiiiciency, while the remaining ones can be cut out and thereafter will consume no current at all.

2. In an electrically heated steam generator, outer cellular structure comprising a plurality of vertically disposed tubes open at both ends and arrange side by side, each such tube constituting the envelope of a separate steam generating cell, each cell comprising a water tube, an electrical heating element within each tube adapting each tube to perform as an independent steam adapted to join said tubes in multiples, a system of water inlet and steam outlet piping adapted to be connected to all of said headers, and current controlling apparatus operatively connected to the heating elements in each tube, whereby the generation of steam within one tube or group of tubes may be started or stopped as desired.

3. ln an electrically heated steam generator an outer cellular structure comprising a plurality oi' vertically disposed tubes open at both ends and arranged side by side, each such tube constituting the envelope of a separate steam generating cell, said cells being grouped in a plurality of separate but interconnected sections, each section comprising a plurality of such Vertically dispesed tubes, an electrical heating means within each tube, water and steam headers joined to said tubes, a system of piping joined to all the water and another system of piping joined to all the steam headers.

4. A multiple-unit, electrically heated, steam boiler comprising, in combination, a plurality of steam headers of uniform construction supported over an equal number of similarly arranged water headers, each pair of headers being connected to- -gether by a row ci vertically arranged water tubes and each steam header having an opening in its upper wall registering with a water tube opening beneath, a system o piping adapted to be connected to all of said steam headers for discharging steam therefrom and another system of piping adapted to be connected to all said water headers for delivering feed water thereto; together with a plurality of standardized electrical heating units each contained in a Water tight envelope open at one end, which envelope is adapted to be inserted through any one of said steam header openings with its closed end projecting into the water tube registering therewith, and means for releasably securing the other end of each of said envelopes to the upper wall of said steam header and forming a steam-tight joint between the two.

5. A combination such as deiined in claim 4 in which each of said systems or piping comprises a U--shaped conduit having a branch at its curved portion and a plurality of inwardly extending branches along each arm of the U adapted to be connected to the header ends.

6. A combination such as defined in claim 4 in which the interior of each water tube is provided with yielding, inwardly extending projections between which the closed end of a heater envelope may be inserted to center the same in said tube interior, While permitting both radial and axial expansion or contraction therein.

'7. A combination such as defined in claim 4 in which the joint-forming means between one end oi said heater envelope and said steam header comprises an annular shoulder in said header opening, an outwardly flanged lip on said envelope and an annular nut threaded into said header opening and bearing on said flanged lip, in which annular nut said heating unit is supported.

8. In an electrically heated boiler the combination of an elongated steam header having a series of openings in its upper wall and a series of openings of slightly larger diameter in its lower wall, each such lower opening being c0- axial with one of the upper openings, a plurality oi water tubes anged into and projecting from said lower openings, a plurality of heater envelopes each having an open outwardly flanged and adapted to be seated in any one of said upper wall openings, and screw threaded means for forcing said flanges against their seats to form steam-tight joints.

9. A structure such as deiined in claim 8 combined with a resistor adapted to be inserted in said envelope while supported by said screw threaded means, and electrically insulating means forming said resistor support.

10. In an electrically heated steam generator the combination of a plurality of sectional steam header and water headers joined together in pairs by vertically arranged water jackets, a water tight envelope open at the upper end adapted to be inserted within any of the said water jackets, an electric heating unit adapted to be supported in said envelope and means for releasably securing the open end of said envelope to the upper wall of the steam header and for forming a steam tight joint between the two. 110

11. A combination such as dened in claim 10 in which the interior of each water jacket is provided with means to frictionally engage the sides of the lower end of Laid envelope; whereby said envelope may be permitted to expand and 115 contract longitudinally independently of said water jacket.

12. A combination such as defined in claim 3, in which each such section has its seprate pair of headers.

13. A combination such as defined in claim 3 in which each such section has its separate pair of headers, each connected at both ends to its cooperating system of piping.

lfl. An apparatus such as defined in claim 3 125 combined with a current supply circuit to which the said electrical heating means are connected in multiple, a switch for controlling the flow of current to each cell heater, and a group circuit breaker for simultaneously controlling such flow 13(4 of current to all the cells in any one section.

GUS L. COLBIE.

sstttttncntn oF sonnscitton,

Patent No. 1,928,446. September 26, 1933.

GUS L. comm.

lt is hereby certified that efror appears in the printed specification of the above numbered patent requiring correction as follows: Page 4, line 91, slaim 8, fot' "and" rend "end"; and that the said Letters Patent should be read with this :correction therein that the same may conform to the record of the case in the Patent Glice.

Signed and sealed this 24th day of October, A. D. 1933.

F. M. Hopkins (Seal) ,Y Acting Commissioner of Patents.

nnntintnn'tn or oonnnorion,

Patent No. ini/328,446. September 26, 1933.

ons L. comm.

Et is heroby dicertified that error appears in the printed specification of the ahove nninbered patent requiring correction as follows: Page 4, line 91, claim 8, for "and" rend "end; and that the said Letters Patent should be read with this sorrecon therein that the same may conform to the record of the oase in the Patent Office.

Signed and sealed this 24th day of October, A. D. 1933.

F. M. Hopkins (Seal) Acting Commissioner of Patents. 

